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E. P. HOWLAND.

VINHALING AIR CHAMBER POR DENTAL AND SURGICAL OPERATIONS, 8m.

No. 280,040. Patented June 26, 1883.

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UNITED STATES PATENT OFFICE.

VEDVIN P. HOVLAND, OF VASHINGTON, DTSTRICT OF COLUMBIA.

INHALING AIR-CHAMBER FOR DENTAL AND SURGICAL OPERATIONS, &c. A

SPECIFICATION forming part of Letters Patent No. 280,040, dated June 26,1883.

Application llcdMay 12, 1893. (No model.)

To all whom it may concern: p

Be it known that l, EDWIN P. HowLAND, of Washington, in the District ofColumbia, have invented certain new and'useful improvements incondensed-air chambers in which to administer nitrous oxide and air ornitrous oxide and oxygen to persons to produce antesthesia for dentaland surgical operations; and l. do hereby declare that the following isa full, clear, and exact description thereof', reference being had .tothe accompanying drawings, making a part of this specification, inwhich- Figure l is a perspective View of a condensedair chamberconstructed in accordance with my improved method. Fig. 2 is a sectionalView ofthe same." 'L

Letters of like name and kind refer to like parts in each of thefigures.

The design of my invention is an apparatus for the purpose ofadministering nitrous oxide and air or nitrous oxide and oxygen in acondensed-air chamber, to produce antesthesia inv persons to whom it isadministered, and at the same time oxygenate the blood and produceanaesthesia for short or long dental and surgical operations, withoutthedangerous and unpleasant effects of ether and chloroform, and at thesame time have tlie air of the chamber free from impurities andgerms ofbacteria that might inoculate the patient during operations frominfected air in contact with open wounds. ln the administration ofnitrous oxide for dental and surgical operations as ordinarilyadministered, the gas has to be almost absolutely free from air oroxygen, and does not arterialize the blood, and, if continued withoutbreathing air or oxygen, will produce asphyxia, thereby requiring greatskill and experience in administering it for prolonged operations, andtherefore the gas has not come into general practice for theseoperations. A certain amount of nitrous oxide taken into the lungs in agiven time is necessary to produce antesthesia, and it can be dilutedwith any innocuons gas and still produce an zesthesia, provided thisamount is inhaled in the given time. Under pressure in a chamber moregas is breathed in a given time, as the nitrous oxide is condensed thesame as the air in the chamber, and under a pressure of two atmospherestwo volumes of nitrous oxide would be condensed into one volume, so thatthe nitrous oxide could be diluted with equal measures of atmosphericair and stillthe quantity of nitrous oxide inhaled would be the same asif breathed ordinarily, and they quantity of air breathed sufficient toarterialize the blood. \Vhen amixture of nitrous oxide and oxygen isbreathed in a condensed-air chamber, a less degree of compression of airin Vthe chamber will produce anaesthesia and oxygenation of the bloodthan when the mixture is nitrous oxide and air.

My invention to obtain the results stated consists, principally, of anair-chamber, chamber-recess, filtering-chamber, condensed-air reservoir,pump, pipes, cocks, valves, doors, sliding rods, a condensed nitrousoxide and air or nitrous oxide and oxygen reservoir, gasbag, andbreathing apparatus.

I willnow proceed to more particularly describe the construction andoperation of my invention, referring in so doing to the drawings annexedby letters of reference marked thereon.

A is a strongly-constructed air-chamber for withstanding pressure, inwhich dental and surgical operations are performed.

B is a chamber-recess, with an outer door, G, and an inner door, K, soarranged that persons can pass into and out of the air-chamber A withoutinterrui'iting operations or discharging air from air-chamber A; H, cockin chamber-recess B, connected by pipes C and D with filtering-chamber Fand condensed-air reservoir R, so that condensed air can beadmitted tochamber B and discharged from cock H without affecting or changing thepressure of the air in the air-chamber A, consequently not altering theproportions of gas being breathed by the patient. y i

L is a sliding rod connected with cock H, and passing through astuffing-box into airchamber A, and used for opening and shutting cockH.

`L is a sliding rod connected with cock H,

and passing through a stuiing-box to outside of chamber-recess B, andused for opening and shutting cock H.

F is a ltering-chamber filled with material, through which the air inpassing is freed from impurities and infectious germs.

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R is a large condensed-air reservoir, filled by pump B `through pipe D.

G is a cock in air-chamber A, and connected by pipes C and D withfiltering-chamber F and air-reservoir B, so that condensed air can beadmitted to air-chamber A. G is a cock for discharging air fromair-chamber A.

M is an automatic valve to open and shut cock G at required pressure inair-chamber A, so that in filling chamberrecess B with condensed airfrom reservoir B no condensed air can be drawn from ahr-chamber Athrough pipe C and equal pressure keptin air-cham-V ber A at all times.

E is an automatic valve for regulating the pressure of air inair-chamber A and for ventilation of chamber. Y

E is an automatic valve for regulating the pressure of air in thechamber-recess B.

B is a condensed-gas reservoir for nitrous oxide and air or nitrousoxide and o'ygen.

S is a gasbag in connection with gasreser` voir B and mouth-piece T,through which the patient inhales.

'U and U are incandescent electric lamps for illuminating theair-chamber A.

V are wires in connection with electric supply for cauterization andsurgery.

N and N are gages for registering pressure of air in air-chamber A andchamber-recess B.

The chambers are operated as follows: The air-chamber A, having beenpreviously filled with condensed air to the required pressure, thepatient and attendants enter the chamberrecess B through the door G. Thecock H is then opened till the pressure in the chamber-recess B is thesame as in air-chamber A, when the door K is opened and the patients andattendants enter the air-chamber A. The condensed nitrous oxide and airor nitrous oxide and oxygen is then administered to the patient for anylength of time that it is necessary to perform the dental or surgicaloperation. In passing out of airehamber A when operations are beingperformed the ch am ber-recess B is entered through.

lthe door K, the cock H is opened, and the condensed air is dischargedfrom chamber-re cess, when egress can be had through door G withoutaffecting pressure in air-chamber. ln passing out ot' air-chamber A, ifthe con,-

densed air in chamber-recess B has been discharged, the cock H is openedby the sliding rodL till the condensed air in chamber-recess B has thesame pressure as air-chamber A. Vhen the chamber-recess is entered bydoor K, the condensed air is then discharged from chamber-reeess by cockH', when egress can be had through door G. In entering airchainber Avwhen chamber-recess B is filled with condensed air, the condensed airin chamber-recess B is first discharged by opening the cock H by meansof the sliding rod L,when the chamber-recess is entered by door G, andthen filled with condensed air by opening cock H till the pressure issame as air-chamber, when the -air-chamber can be entered by door K.

Having thus fully set forth the nature and merits of my invention, whatl. desire to claim and secure by Letters Patent isl. The combination ofthe air-cha1nbcr A with chamber-recess B, filled with condensed airindependently from air-chamber A, as and for the purposes shown anddescribed.

2. The combination of the air-chamber A and chamber-recess B with theair-'filtering chamber F,to free the air from impurities and infectiousgerms before entering air-chamber A and chambcr-recess B, substantiallyas and for the purpose set forth.

3. The combination of the air-chamber A and chamber-recess B with thesliding rods L and L, for opening and shutting cocks H and` H', for thepurpose of letting condensed air into and out of chainbenrccess B,substantially as set forth and described.

ait. The combination of the airchainber A, chamber-recess B, and otherdevices, described, with the automatic valve M, for open` ing andshutting cock G at required pressure in air-chamber A, so that infilling chamberrecess B with condensed air from reservoir B no condensedair can be drawn from air-cham ber A through pipe C, and equal pressurekept in. air-chamber A at all times, substantially i'or the purposeshown.

EDVIN P. HOVLAND.

Witnesses CLARENCE H. HowLAND, J. SHILLINGTON.

